Why did Axl Rose fill in for ACDC?

Can you explain the reasoning behind Axl ROSE stepping in to fill the void for AC/DC? Was there a specific need that arose within the band that necessitated his involvement? Or was it a creative decision to bring a new element to their sound? It's intriguing to see a lead singer from a different band like Guns N' Roses take on such a pivotal role in AC/DC's performances. What were the circumstances leading up to this unexpected collaboration, and what do you think it says about the flexibility and adaptability of both bands?